1. Field
The present embodiments relate to an optical filter and an organic light-emitting device including the same.
2. Description of the Related Technology
Typically, an organic light-emitting device includes an anode (first electrode), a cathode (second electrode) and an organic layer interposed between the anode and the cathode. In the organic light-emitting device, as a voltage is applied between the anode and the cathode, holes are injected from the anode to the organic layer, while electrons are injected from the cathode to the organic layer. The holes and electrons injected into the organic layer combine to generate exitons. When the exitons drop from an excitation state into a ground state, light is emitted.
In the organic light-emitting device, the anode constitutes a reflective electrode, whereas the cathode constitutes a transparent electrode. Thus, when the organic light-emitting device operates, light emitted from the organic layer is reflected from the reflective electrode and is externally emitted by passing through the transparent electrode.
In this regard, nearly 100% of internal light is externally emitted, whereas about 40% of external light is reflected. As a result, an image may appear incomplete. In particular, dark colors of the image may not be sufficiently discernable, so that a contrast ratio and visibility of the image may be lowered. Thus, a polarizing film may be attached to an external surface of the organic light-emitting device in order to reduce the reflection of external light.
Reflectance of the external light may be lowered to about 4% due to the attachment of the polarizing film having the structure described above. However, transmittance of the internal light may also be lowered to about 43%, thereby causing loss of light. Therefore, there is a demand to reduce such a loss of light and power consumption that is greater due to the higher-luminance of the organic light-emitting device.